1. Field of the Invention
The present invention relates to optical storage systems, and more particularly, to an input sampling circuit and a method for processing a disc read back signal.
2. Description of the Prior Art
Recently, optical storage technologies, such as CD and DVD, have become the main stream for storage media applications due to their portable characteristic and high storage volume. Usually, when processing a disc read back signal read from a pickup, an optical disc drive system utilizes an analog-to-digital converter (ADC) to sample the disc read back signal, and generate corresponding digital data for subsequent digital signal processing operations.
However, as the rotational speed of the optical disc drive system increases along with the progress of technology, thereby causing high speed applications to be introduced, the sampling rate of the ADC also increases accordingly and can even reach up to the degree of several hundred MHz. In addition, in order to maintain the sampling resolution of the ADC above certain level when the ADC performs analog-to-digital conversion on the disc read back signal, the number of bits of the digital data generated by the ADC may not be decreased. Usually, the number of bits is designated six bits or more. As a result, the optical disc drive system suffers larger die size and higher power consumption of the ADC within.